1. Field of the Invention
The invention relates to the field of stabilized oscillators and more particularly to stabilized oscillators which provide a train of square wave pulses synchronized to an applied gating signal.
2. Description of the Prior Art
A gated rectangular pulse oscillator in the prior art utilized a RC circuit to establish a relaxation oscillator after a gating signal was applied The oscillation period of these devices is a function of the resistor R, the capacitor C, and the high and low transition voltages Since these values may vary with temperature the oscillation period may also vary. Thus, the oscillation frequency of these devices varies with temperature. Further, the switching voltages are modulated by circuit noise, causing the leading and trailing edges of the oscillator pulses to jitter in a random fashion.
A stabilized oscillator that exhibits greater frequency stability and improved edge jitter performance, relative to the RC relaxation oscillators is disclosed by David C. Greene in U.S. patent application Ser. No. 304,698 filed on Jan. 31, 1989, now U.S. Pat. No. 4,904,962, assigned to the Assignee of the present invention, and incorporated herein by reference The oscillator disclosed in application Ser. No. 304,698 utilizes an LC resonator as the frequency controlling element. This circuit appreciably improves the frequency stability and significantly lowers the edge jitter relative to that of the RC relaxation oscillator. The coils, however, are relatively large and the circuit requires tuning due to the inductive tolerance range within which the coils may be manufactured. This tuning adds an additional step in the manufacturing process and coupled with the price of the coil renders the LC controlled gated oscillator relatively expensive.